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Modeling plasma physical processes in astrophysical context demands for both detailed kinetics and large scale development of the electromagnetic field densities. We present a new framework for modeling plasma physics of hot tenuous plasmas by a two-split scheme, in which the large scale fields are modeled by means of a particle-in-cell (PIC) code, and in which binary collision processes and single-particle processes are modeled through a Monte-Carlo approach. Our novel simulation tool—the PHOTONPLASMA code-is a unique hybrid model; it combines a highly parallelized (Vlasov) particle-in-cell approach with continuous weighting of particles and a sub-Debye Monte-Carlo binary particle interaction framework. As an illustration of the capabilities we present results from a numerical study [1] of gamma-ray burst-circumburst medium interaction and plasma preconditioning via Compton scattering. We argue that important microphysical processes can only viably be investigated by means of such “trans-Debye scale” hybrid codes. Our first results from 3D simulations with this new simulation tool suggest that magnetic fields and plasma filaments are created in the wakefield of prompt gamma-ray bursts. Furthermore, the photon flux density gradient impacts on particle acceleration in the burst head and wakefield. We discuss some possible implications of the circumburst medium being preconditioned for a trailing afterglow shock front. We also discuss important improvements for future studies of GRB wakefields processes, using the PHOTONPLASMA code. [ABSTRACT FROM AUTHOR]